Prospective comparison of contrast-enhanced computed tomography versus magnetic resonance venography in the detection of occult deep pelvic vein thrombosis in patients with pelvic and acetabular fractures.

Objective: To determine the rate of pelvic vein thrombosis following acetabular or pelvic fracture identified by enhanced computed tomography venography or magnetic resonance venography.

Design: Prospective evaluation of computed tomography venography and magnetic resonance venography in patients with pelvic and acetabular trauma as a screening tool for deep vein thrombosis.

Setting: Level I trauma center.

Results: Thirty patients with pelvic or acetabular fractures and who met the study criteria were prospectively screened with magnetic resonance venography and computed tomography venography to determine preoperative presence of pelvic venous thrombosis. Pelvic deep vein thrombosis was detected by computed tomography venography in two patients (7%) and by magnetic resonance venography in four patients (13%). Invasive selective pelvic venographies were performed on the five subjects who tested positive on either one or both screening tests. Only one computed tomography venography case was validated by invasive pelvic venography. The false-positive rate for computed tomography venography was 50%, and the false-positive rate for magnetic resonance venography was 100%.

Conclusions: We cannot recommend the sole use of either computed tomography venography or magnetic resonance venography to screen and direct the treatment of asymptomatic thrombi in patients with fracture of the pelvic ring because of the high false positive rates. If these studies are used as screening tools, confirmation of the presence of thrombosis with selective venography should be performed prior to initiating invasive treatment with a vena cava filter. Clinical decisions based solely on one of these imaging techniques may result in inappropriate aggressive treatment due to the high false-positive rate.